In general, the solar aureole is hardly evident on a clear day with no airborne particles but grows in size in hazy conditions and/or in the presence of airborne particles.
Observing and imaging the solar aureole is of interest in various fields: determining the quantity, size, shape, distribution and type of airborne particles; correcting for the effects of clouds between a satellite mounted imager and a light source below the cloud; and in climate studies.
The problem of observing the aureole is similar to that of observing the solar corona. The usual equipment for imaging the aureole or corona is a coronagraph which includes an opaque disk or “occulter” just large enough to blot out the solar disk. See B. Lyot, “La Couronne Solair Etudiee en Dehors des Eclipses”, Comples Rendus de L'Acadimie des Sciences, Paris 191, 834 (1930). See also, C. L. Strong, “A Coronagraph to View Solar Prominences”, Scientific American, The Amateur Astronomer, pp. 99-103 (1955). See also Ritter, J. and Voss, K., “A New Instrument for Measurement of the Solar Aureole Radiance Distribution from Unstable Platforms”, The Journal of Atmospheric and Oceanic Technology, Vol. 17, pp. 1040-1047 (American Meteorological Society, 2000). These three references are incorporated herein by this reference.
Commercially available coronagraphs, however, are extremely expensive, limited in supply, and include numerous precision optical surfaces.